DRY AIR ... PRECISELY os you want it t o c o n t r o l y o u r p r o d u c t ' s quality t o p r e v e n t c o n d e n s a t i o n o n y o u r p r o d u c t o r material t o p r e v e n t c h a n g e s d u e t o m o i s t air i n c o n t a c t w i t h y o u r p r o d u c t t o p r o t e c t y o u r m a t e r i a l from d a m p n e s s t o p r o t e c t y o u r p r o c e s s i n g o f moisture-sensitive m a t e r i a l t o D R Y y o u r material o r p r o d u c t t o p a c k o r store y o u r p r o d u c t safe from m o i s t u r e d a m a g e t o g e t exact m o i s t u r e c o n t r o l for t h e precise a t m o s p h e r e condition you need t o p r o v i d e precise a t m o s p h e r i c c o n d i t i o n s for t e s t i n g t o increase your air c o n d i t i o n i n g capacity t o D R Y large quantities o f fresh air from o u t d o o r s
The Niagara's Controlled Humidity Method using HYGROL moisture-absorbent liquid is Best and most effective because . . . it re moves moisture as a separate function from cooling or heating and so gives a precise result constantly and always. Niagara machines using liquid contact means of drying air have given over 20 years of service.
The cleanest because . . . no solids, salts or solutions of solids are used and there are no corrosive or reactive substances.
Most reliable because . . . the absorbent is continuously reconcentrated automat ically. No moisture-sensitive instruments are required to control your conditions. Most flexible because . . . you can obtain any condition at will and hold it as long as you wish in either continuous produc tion, testing or storage. Easiest to t a k e care of because . . . the
apparatus is simple, parts are accessible, controls are trustworthy. Most compact, taking less space for in stallation. Inexpensive
to o p e r a t e
because . . . n o
re-heat is needed to obtain the relative humidity you wish in normal tempera ture ranges and frequently no refrigera tion is used to remove moisture. Write for full information;
N i a g a r a Controlled Humidity Air Conditioning This method removes moisture from air by contact with a liquid in a small spray chamber. The liquid spray contact tem perature and the absorbent concentra tion, factors that are easily and positively controlled, determine exactly the amount of moisture remaining in the leaving air. Heating or cooling is done as a separate function.
ask for Bulletins
112 and 121. Address
Dept.E.C.
N I A G A R A BLOWER C O M P A N Y 4 0 5 Lexington Ave., N e w York 17, Ν . Υ. District Engineers in Principal Cities of U. S. and Canada For further information, circle number 58 A on Readers' Service Card, page 139 A 58 A
INDUSTRIAL A N D ENGINEERING CHEMISTRY
consumer d e m a n d s for better quality products. Since catalytic cracking stocks a r e primarily virgin distillates which normally would be blended into distillate a n d residual fuels, t h e re sulting loss in distillate volume must be balanced by the use of lower qual ity cracked distillates. Also, where virgin stocks from sour crudes a r e available for these products, t h e quality is insufficient to meet current requirements. Consequently, t h e gasoline octane race h a s m a d e it virtually impossible to produce good quality distillate a n d residual fuels without specialized refining process ing. This special processing has been directed toward the elimination of three undesirable characteristics of distillate a n d residual products : cor rosion, deposit-forming tendencies, and instability. Sulfur content has been found to be related to each of these, especially corrosion a n d deposit formation. Consequently, a very strong trend toward lower sulfur specifications has developed in the past few years. Sulfur is especially critical for dis tillates—i.e., Diesel fuel a n d heating oil—in which corrosion a n d objec tionable odors a r e particularly u n desirable. For heavier residual oils, in addition to sulfur, trace metals have been found to promote high temperature corrosion. T h e problem of deposit formation has increased with t h e trend to use heavier flux stocks for residual prod ucts. Higher operating tempera tures a n d pressures for industrial installations utilizing material such as fuel oil have accentuated the for mation of deposits. Instability in distillates is primarily due to unsaturated a n d oxygenated compounds a n d , to a lesser degree, nitrogen content. M e r c a p t a n sul fur also appears to be undesirable from a stability standpoint because of its reactive nature. Hydrotreating. Hydrotreating, a moderate pressure, catalytic hydro génation process of a very flexible nature, appears to be a major solution to this quality problem. H y drotreating of distillate a n d residual stocks results in a large reduction in sulfur content a n d carbon residue, and also improves burning characteristics, stability, color, a n d odor. Applying this process to the treating of catalytic cracking feed stocks
